Erik Verfuss

I had the same issue on a 2015.5 2500 Denali and they also told me that it was the trailers (2 of them), although both worked fine with other vehicles. After several trips to the dealer, I mentioned it to my trailer dealer/hitch installer - he said that it the truck monitored amperage (actually milliamps) draw at the plug and that there must be an increased draw somewhere. He cleaned the connections in the truck side of the plug - issue went away. When it reappeared after a winter of snow and ice, he replaced the receptacle/plug in the bumper and the issue never returned...